1. Field of the Invention
This invention relates to the removal of dissolved sulfides from a sulfuretted carbonate containing water, particularly for the reduction of environmental pollution from discharge of said water, and for recovering hydrogen sulfide therefrom.
2. State of the Art
Carbonate containing waters contaminated with dissolved sulfides occur naturally as waters from subterranean sources, including geothermal sources, and have also resulted from many industrial processes. Such waters include mineral spring waters, condensates of geothermal steam, aqueous condensates from coke oven gases, wash water from scrubbing of industrial gases containing hydrogen sulfide and from gases produced by anaerobic digestion of sulfur-containing organic matter such as sewage and garbage, and effluents from pulp mills, rayon plants, etc. Certain of such contaminated waters, depending on their origin, contain one or more additional contaminants which may include ammonia and substances comprising arsenic and/or mercury. Hydrogen sulfide in aqueous solution is known as hydrosulfuric acid and its oxidation products, sulfurous and sulfuric acids, are corrosive to many metals utilized in industry. Furthermore, hydrogen sulfide is a noxious malodorous material detrimental as an environmental pollutant, as also are the arsenic and/or mercury components referred to.
Heretofore, such contaminated waters have usually been discharged to the environment with resulting odorous and noxious pollution. Attempts to obviate pollution have included processes for the treatment of such waters with air, usually in the presence of a dissolved catalyst, or by chlorination, to oxidize the hydrogen sulfide to elemental sulfur, with consequent pollution of the environment by the resultant non-odorous reaction products. Such abatement practices are expensive as well as creating alternate pollution problems. Other attempts to minimize pollution by such waters have included conventional flashing and stripping, but such processes remove only volatile dissolved sulfides, e.g., dissolved hydrogen sulfide gas, leaving sulfide salts, e.g. ammonium sulfides, sodium sulfides, etc., in the waters, whereby these other practices have been only partially effective.